Improving a 2012 LML Duramax
This Silverado 2500HD project was introduced in the March issue of Diesel World, so if you haven’t seen it, go snag a copy and get fully up to speed. You’ve missed just Part One of the build and the backstory behind what it’s about, so we’ll quickly recap. I had been driving a 2002 LB7 Duramax for almost 6 years, used it for what most owners used their trucks for it was my daily driver, hauled kids to pre-school and dragged our family fifth wheel all over the mountains of Utah and Southeast Idaho camping. In those 6-years it turned from a basically stock capable pickup into a fully built 750hp twin turbo street stomper that could still do all the things I needed to on a day to day basis. It was a lot of fun to build and even more fun to drive. Unfortunately, the love affair was ending and newer technology, quieter engines, and comfier leather seats had been calling my name and it was time to search for a truck to replace it and start over with.
After selling that built LB7 and searching used car lots and classified ads, this fully loaded 2012 LML Duramax caught my eye. For the first part of the build-up I had to do something about the stock horsepower level, as jumping out of 750hp and into 350hp was not only a hit to my pride, but a bore to the driving experience. The LML engine used in 2011-2016 GM trucks makes respectable power in stock form and is more than capable of towing just about anything you want, but the aftermarket can always find a bit more on tap with a few tweaks. The newest Jammer Stage 2 kits from Edge Products offer a cold air intake, high flow stainless steel exhaust system and their Evolution CTS2 monitor and tuning device that all work together to produce efficient, usable, CARB and emissions-friendly horsepower. The kit specific to this truck was all very easy to install and literally took less than an hour to do it all. With the improvements to airflow being fed to the engine, the modifications to the ECM programming and better flowing tailpipe system this truck gained 127hp and over 200lb-ft of torque. Now we won’t be daily driving the truck in that 500hp tune until we do a few more supporting mods like a fuel lift pump, but even in the Towing program the truck still produced over 440 rear-wheel horsepower and helped bump the mileage up to a solid 17-18mpg average.
DRP 3” Hot Side Pipe
To take the airflow side of things one step further, the factory driver side intercooler pipe on 2011-2016 trucks uses a somewhat restrictive 2.5” two piece tube to connect the turbo outlet to the intercooler inlet, where that 2.5” pipe expands out to meet the 3” inlet of the charge air cooler. It seems like simple logic in the way air flows through something, that a large diameter could move more volume with less restriction. To help remedy this, Deviant Race Parts (DRP) of Hayden, ID developed a full 3” high flow hot side intercooler pipe that easily replaces the stock unit. By removing the front driver side inner fender well liner, you get pretty easy access to the charge air pipe and can disconnect it from the intercooler and turbocharger and fish it up and out of the engine bay from above. The DRP piece not only uses a large diameter pipe to improve airflow to the intercooler, but they’ve gone to great lengths to ensure easy airflow passage through mandrel bent tubing and leak free sealing with rolled beads at each end, and super tough silicone boots to connect it all. DRP again uses the two-piece pipe design to make installation easier, but has moved the junction a little further up on the pipe to make access to the clamps and boot easier.
The larger hot side pipe has shown lower EGT’s under load, quicker turbo spool-up and a slight increase in power on the chassis dyno (10hp). The fit is near perfect with no rubbing anywhere under the hood and it comes standard coated in a gloss black powder coat for a great look. The two-piece pipe kit includes the required 3” boots and 2.5”-3” reducer boot for the turbocharger connection. Factory style t-bolt clamps are included as well. Moving forward, we’ll look at upgrading to a better flowing and more efficient intercooler and Y-bridge assembly to compliment a mild turbocharger upgrade, so this 3” hot side pipe was the perfect place to precursor those changes.
Bestop EZ-Roll Tonneau
This truck is already 5-years old and has 117k miles on the odometer, but its condition really couldn’t be better. It was apparent the previous owner took good care of the truck and kept up on regular maintenance. The Carfax report showed good records and also informed us the truck had spent its previous life in British Columbia, Canada. That helps explain some of the dirt buildup on the chassis below and that big fiberglass shell. I’m sure braving the long cold winters and dirt roads isn’t an easy task, but a truck shell would have some definite benefits trying to keep equipment and your belongings dry in the bed. Since I plan to use this truck in the summers to haul a 29-ft fifth wheel camp trailer and the shell just screamed ‘grandpa’, it took very little time get it removed. However, I to live in a cold climate that sees snow and nasty weather for a few months of the year so keeping the bed area dry and clean is necessity for me to.
My last truck had a roll-up tonneau cover installed and I swore I’d never own another truck without one. Bestop offers a few versions of roll-up bedcovers and their EZ-Roll soft cover seemed the perfect fit for the build. The sleek low-profile cover hugs the bedsides nicely for a good look, but offers great functionality as well. Easy no-drill installation took less than 15 minutes by myself in the driveway and the treated leather grain vinyl-coated polyester will withstand any climate and offer great UV protection. The simple hook-n-loop fastening system allows the cover to roll conveniently at the front bed rail to allow full access to the entire bed area. The EZ-Roll was the perfect answer for bed storage protection and easy gooseneck hitch accessibility when needed.
So part two of this build wasn’t quite as exciting as part one, we didn’t get to bolt on another 127hp like we did last month with the Edge Jammer Stage 2 kit. But this project build isn’t just about making horsepower. The whole goal is to make a stock used truck more user friendly, how to outfit your truck to be best suited for your particular needs. Of course, being a diesel junky, more horsepower under the hood will come with time, but we need to start adapting this truck to fit a particular lifestyle and show you readers what’s available to help you accomplish that. The truck shell that came on the truck had a purpose, sure, but towing a fifth wheel trailer was out of the question, so if you have the need to protect things in the bed of your truck, but still need full access for towing or hauling stuff in the bed, the Bestop EZ-Roll tonneau cover is easy on the checkbook and a super simple installation. With plans of performance fuel system parts and replacing the stock turbocharger with something bigger, improving the stock charge air system will never be wasted money. The Deviant Race Parts 3” high flow hot side pipe, again, is inexpensive and easy to install. Better turbo response, lower EGT’s and a perfect fit, so it meets the form and function criteria required for this build. A no-brainer, bolt-on part to help turn this ordinary used truck into the ultimate family oriented daily driver tow rig.
Deviant Race Parts